Noise++ Perlin Module returns 0 all the time

Question

Im using the Noise++ Library to generate noise in my program, well at least thats the aim. I have it setup like one of the tests in order to test it out, however no matter what parameters I give it I only get 0 back

If anyone has any experience with Noise++ it would be really helpful if you could check over and see if im doing anything wrong.

//
// Defaults are
// Frequency    =   1
// Octaves      =   6
// Seed         =   0
// Quality      =   1
// Lacunarity   =   2
// Persistence  =   0.5
// Scale        =   2.12
//

NoiseppNoise::NoiseppNoise( ) : mPipeline2d( 2 )
{
    mThreadCount = noisepp::utils::System::getNumberOfCPUs ();

    mPerlin.setSeed(4321);
    if ( mThreadCount > 2 ) {
        mPipeline2d = noisepp::ThreadedPipeline2D( mThreadCount );
    }

    mNoiseID2D = mPerlin.addToPipe ( mPipeline2d );
    mCache2d = mPipeline2d.createCache();
}

double NoiseppNoise::Generate( double x, double y )
{
    return mPipeline2d.getElement( mNoiseID2D )->getValue ( x, y, mCache2d );
}

I thought the threading was all done internally, ie: the user (in this case me) doesnt have to worry about threading issues — Richy19, Oct 25 '13 at 00:29

score 1 · Accepted Answer · answered Oct 25 '13 at 02:04

I have added the following lines to your code to compile (basically no changes except for cleaning the cache):

struct NoiseppNoise
{
  NoiseppNoise();
  double Generate( double x, double y );

  noisepp::ThreadedPipeline2D mPipeline2d;
  noisepp::ElementID mThreadCount;
  noisepp::PerlinModule mPerlin;
  noisepp::ElementID mNoiseID2D;
  noisepp::Cache*  mCache2d;
};

/* constructor as in the question */

double NoiseppNoise::Generate( double x, double y )
{
  mPipeline2d.cleanCache (mCache2d);  // clean the cache before calculating value
  return mPipeline2d.getElement( mNoiseID2D )->getValue ( x, y, mCache2d );
}

Calling it with

NoiseppNoise np;
std::cout<<np.Generate(1.5,1)<<std::endl;

actually outputs a good value, 0.0909 for me.

However if you call it with two "integers" (e.g. 3.0 and 5.0) the output will be 0 because at some point something similar to the following statement is executed:

const Real xs = Math::CubicCurve3 (x - Real(x0));

If the parameters are integers then x and Real(x0) are always the same because Real(x0) is basically the integer part of x and so xs will be set to 0. After this there are more calculations to get the actual value but it becomes deterministically 0.

Noise++ Perlin Module returns 0 all the time

1 Answers1